ORION-1 is a placebo-controlled, double-blind, randomized Phase II trial of single or multiple subcutaneous injections of PCSK9si in patients with atherosclerotic cardiovascular disease (ASCVD) or ASCVD-risk equivalents (e.g., diabetes and familial hypercholesterolemia) and elevated LDL-C despite maximum tolerated doses of LDL-C lowering therapies. The study compares the effect of different doses of PCSK9si and evaluates the potential for a quarterly or bi-annual dosing regimen. The primary endpoint of the study is the percentage change in LDL-C from baseline at Day 180. The study exceeded its enrollment target of 480 patients ahead of schedule, enrolling a total of 501 patients between January 21, 2016 and June 2, 2016.